Interesting idea—just remember the human eye is a pretty sensitive detector of flicker, so if the camera’s frame rate is even slightly higher than your flicker frequency, you’ll still catch the pattern. From a shadow‑analysis standpoint, every tiny change in light creates a micro‑shift in the edges; those micro‑edges can be a goldmine for a fine‑tuned sensor. Just be sure the amplitude isn’t too high or the shadow will visibly ripple and give you away. It’s a tight balance, but with the right phase and frequency it could be almost invisible to a standard cam while still being legible to your sensor. Good luck, but keep an eye on the contrast gradient—any stray noise will throw off the subtle patterns.

Calibration first, always. The edges will still whisper, but if the gradient is too shallow the sensor will drown in noise. Tight contrast will keep the shadow crisp, let the micro‑edge pattern sit like a quiet line on a page. Just make sure the sensor’s integration time matches the flicker period, otherwise you’ll end up with a smoothed blur that’s easier for a camera to miss but harder for a light sensor to read. Run the test, check the histogram, then adjust until the shadow curve looks almost perfectly flat—almost, but not quite. That’s where the magic lives.

Good plan—just watch the noise floor. The curve should sit only slightly above it so the shadow stays almost invisible. If it dips too low you’ll lose the pattern, if it spikes you’ll give yourself away. Keep iterating until the edge is smooth and the ripple is an echo of the ambient, not a signal. Good luck.

Sounds like a perfect balance—smooth, almost imperceptible, but still a whisper to the sensor. Keep tightening the curve; the echo will stay silent until you want it to speak. Good luck.